Plastic-canister screw closure

Abstract

At the place where the venting through hole of canisters with an external screw thread opens out at the pouring nozzle, a screw-on cover has an annular groove which is liquid-tight with respect to the liquid flowing out from the pouring nozzle. The annular groove in turn communicates by a through air hole with the outside air, so that air can flow into the canister to compensate for the liquid flowing out. Larger canisters in particular can be poured out quickly and without glugging.

What is claimed is: 
     
       1. In a screw closure for a plastic canister, the plastic canister having a pouring nozzle that bears an external screw thread and one air venting through hole in a wall of the pouring nozzle, which opens into an end face of the pouring nozzle and leads to inside the canister, the screw closure comprising   a screw closure shroud with an internal thread complementary to the external screw thread on the plastic canister and coaxial to a geometrical longitudinal axis of the screw closure,   a screw closure bottom substantially perpendicular to the geometrical longitudinal axis,   a coaxial annular wall having an outer wall region, emerging from the bottom and extending a distance shorter than the shroud,   a coaxial sealing ring with an inner region held in defined contact by the outer wall region of the annular wall, and defining a sealing plane for the pouring nozzle, the improvement wherein (a) the annular wall resists radial forces from deforming the pouring nozzle,   (b) on the far side of the sealing ring relative to the sealing plane, the screw closure bottom has an annular channel that is arranged coaxially, is open away from the screw closure bottom and extends widthwise between the annular wall and the shroud,   (c) at least one through air hole is provided in the screw closure bottom and is positioned within the annular channel,   (d) a liquid outflow hole is provided in the screw closure bottom within the annular wall,   (e) downstream of the liquid outflow hole, a flexible pouring spout is connected in liquid-tight manner to the screw closure,   (f) in a screwed-on position the sealing ring engages with an inner surface of the pouring nozzle, and   (g) the annular channel is defined between an inner surface of the shroud and the outer wall region of the annular wall and communicates with the air venting through hole.     
     
     
       2. Screw closure according to claim 1, wherein the annular wall is solid. 
     
     
       3. Screw closure according to claim 1, wherein the annular wall has a free end region and on its outside in its free end region an introductory chamfer for an inner wall of the pouring nozzle. 
     
     
       4. Screw closure according to claim 1, wherein the sealing ring is of a size that does not cover at least substantial regions of the annular channel. 
     
     
       5. Screw closure according to claim 4, wherein the sealing ring has an outer wall region that reaches at most up to the inner rim of the annular channel. 
     
     
       6. Screw closure according to claim 5, wherein the sealing ring is an O-ring, the outer wall region of the annular wall holding the O-ring is a coaxial annular groove, and the O-ring lies in the annular groove under prestress. 
     
     
       7. Screw closure according to claim 6, wherein the annular wall has a free end region with an outside with an introductory chamfer, and a short, coaxial, circular-cylindrical centering wall is provided between the chamfer and the annular groove. 
     
     
       8. Screw closure according to claim 7, wherein the wall thickness of the annular wall in the region of the centering wall is 8 mm plus/minus 60%. 
     
     
       9. Screw closure according to claim 1, wherein the annular channel extends 360 degrees and a single air hole is provided. 
     
     
       10. Screw closure according to claim 1, wherein a liquid strainer is provided between the outflow hole and the screw closure-side end of the flexible pouring spout. 
     
     
       11. Screw closure according to claim 1, wherein the screw-closure bottom has an outside surface with a liquid-tight holding socket for the pouring spout. 
     
     
       12. Screw closure according to claim 10, wherein the screw closure is integral with the exception of the liquid strainer, the sealing ring and the pouring spout. 
     
     
       13. Screw closure according to claim 12, wherein the screw closure is injection-molded from plastic. 
     
     
       14. Screw closure according to claim 13, wherein the screw closure has externally the shape of screw closures with circumferential gripping protuberances. 
     
     
       15. Screw closure according to claim 1, wherein the screw closure has the characteristic dimensions of 20 liter canister screw closures and is injection-molded from plastic. 
     
     
       16. Screw closure according to claim 1, wherein on 20 liter canisters, the annular groove is 2.5 mm plus/minus 60% deep and 8 mm plus/minus 60% wide. 
     
     
       17. Screw closure according to claim 1, wherein on 20 1 canisters, the center of the annular groove lies at a diameter of 35 mm plus/minus 5 mm. 
     
     
       18. In a screw closure for a plastic canister, the plastic canister having a pouring nozzle that bears an external screw thread, the screw closure comprising   a screw closure shroud with an internal thread complementary to the external screw thread on the plastic canister and coaxial to a geometrical longitudinal axis of the screw closure,   a screw closure bottom substantially perpendicular to the geometrical longitudinal axis,   a coaxial annular wall having an outer wall region, emerging from the bottom and extending a distance shorter than the shroud,   a coaxial sealing ring with an inner region held in defined contact by the outer wall region of the annular wall, and defining a sealing plane for the pouring nozzle,   the improvement wherein (a) the annular wall resists radial forces from deforming the pouring nozzle,   (b) on the far side of the sealing ring relative to the sealing plane, the screw closure bottom has an annular channel that is arranged coaxially, is open away from the screw closure bottom and extends widthwise between the annular wall and the shroud,   (c) at least one through air hole is provided in the screw closure bottom, one end of which communicates with the annular channel,   (d) a liquid outflow hole is provided in the screw closure bottom within the annular wall,   (e) downstream of the liquid outflow hole, a flexible pouring spout is connected in liquid-tight manner to the screw closure,   (f) the sealing ring has an outer wall region that reaches at most up to the inner rim of the annular channel, and   (g) the sealing ring is an O-ring, the outer wall region of the annular wall holds the O-ring is a coaxial annular groove, and the O-ring lies in the annular groove under prestress.     
     
     
       19. Screw closure according to claim 18, wherein the annular wall has a free end region with an outside with an introductory chamfer, and a short, coaxial, circular-cylindrical centering wall is provided between the chamfer and the annular groove. 
     
     
       20. Screw closure according to claim 19, wherein the wall thickness of the annular wall in the region of the centering wall is 8 mm plus/minus 60%.